Electric bell.



S. BROWN.

BLECTRIG BELL.

APPLICATION FILED APR. 29, 1911.

1,01s,'1 62. Patented Feb. 20, 1912.

WITNESSES 6 N'VE/VIOR X. i k AIL 0mg STEWART BROWN, OF ALEXANDRIA,VIRGINIA.

ELECTRIC BELL.

Specification of Letters Patent.

Patented Feb. 20, 1912.

Application filed April 29, 1911. Serial No. 624,150.

To all whom it may concern: I

Be it known that I, STEWART BROWN, a citizen of the United States,residing at Alexandria, in the county of Alexandria and State ofVirginia, have invented certain new and useful Improvements in Elecetric Bells, of which the following is a specification.

My invention relates to electric bells and more particularly to alarmdevices for use in wiring the doors, windows, etc., of a house as aprotection against unauthorized entrance.

The object of my invention is to provide a simple and effectivearrangement of wiring which can be readily connected to a source ofpower by an inexperienced person.

My invention consists broadly in providing an electric bell with twocircuits, one of which when broken will cause the bell to ringconstantly or until the source of electric power becomes exhausted.

In the drawings forming a part of this specification Figure 1 is a planview, and Fig. 2 is a diagrammatic view showing the electric circuits.Fig. 3 is a detail view of arched arm 19.

Referring more specifically t0 the drawings in which like referencenumerals designate corresponding parts in all the views, 1 representsthe base plate preferably of wood having suitable openings2 and 3toreceive screws or other suitable fasteners not shown by means of whichthe base plate and the entire bell may be attached to the wall or othersupport. Secured to the base plate 1 by screws 6 and 7 is a metallicframe 8 comprising a yoke-piece 9, which supports the bobbins 10 and 11,posts 12 and 13 to which are attached respectively the armature 14 andthe armature-carrying spring 15, the latter two members being connectedtogether as at 16, and a forwardly extending arm 17 carrying the bell18. An arched arm 19 is secured to the frame 8 and is insulatedtherefrom as shown at 20. 'The arm 19 carries an adjustable screw 21having a contact point 22 normally in engagement with the free end ofthe armature-carrying spring 15. A series of binding-posts, four innumber and all of usual construction are secured to one end of the baseplate.

At B is shown the battery, which may be placed at any convenient placeto permit connections being made with the electric bell 18. As bestillustrated in Fig. 2, the direct circuit to the battery is illustratedby wires 23 and 24 connected to opposite poles of the battery and to thebinding posts 25 and 26, and the alarm circuit is shown by wires 27 and28 each of which are connected at one end to intermediate binding-posts29 and 30 respectively and as will readily be seen from the followingthe bell and battery are in both circuits. When the alarm circuit isclosed, the flow of current will be from the positive pole 31 of thebat= tery B through wire 23 to binding-post 25 across the connectingwire 35 to bindingpost 29, from where it flows through wires 27 and 28to binding-post 30 and to and through wire 32 connected to the archedarm 19. As previously mentioned the arched arm 19 is insulated from themetallic frame 8. The winding 33 of the bobbins 10 and 11 is connectedat one end to the horizontal portion 34 of the arched arm 19, thusconducting the current through the windings to the binding-post 26 andback to the battery by wire 24. While the current is flowing in thiscircuit the armature 14 is held tightly against the bobbins or magnets.

In practice the wires 27 and 28 forming the alarm circuit are arrangedacross a window or concealed in some other part of a building to guardagainst unauthorized entrance. Should these wires become parted an alarmwould be instantly given by reason of the fact that the current insteadof crossing from the binding-post 25 to the post 29 will flow throughthe continuation wire 33 of the wire 23 to the metallic frame 8, throughthe armature 14 and across to the contact point 22 of screw 21 causingthe bell striker 34 to vibrate. The course taken by the current fromthis point is similar to that described in the previous paragraph, towit, through the bobbins back to binding-post 26 and from thebinding-post 26 to the negative pole of the battery. The bell willcontinue to ring until the alarm circuit is closed or until the batteryplays out.

From the foregoing it will be seen that I have devised an alarm bell ofcomparatively few parts and one which can be readily used and installedby the most inexperienced person.

Having thus described my invention, what I claim is:

In an alarm device, the combination with a base plate of a metallicframe, comprising a yoke, a pair of magnets supported from and connectedto said yoke, an arched arm on said frame and insulated from said frame,a bell, an adjustable contact screw in said arched arm, an armature inelectrical contact with the frame, a spring on said armature having makeand break contact with said adjustable contact point, a pair ofbinding-posts, an electric battery, a wire leading from the positivepole of said battery connected to one of said binding-posts and to saidframe, a wire leading from the negative pole of the battery connected tothe other of said binding-posts and to said magnets and thence to saidarched arm, an alarm circuit comprising a pair of binding-posts, a pairof wires connected to said posts at one end and connected to each otherat their opposite ends, a wire connecting one of said binding poststovsaid adjustable contact screw and a wire extending between the otherof said binding-posts and the binding-post connected to the positivepole 31 of the battery.

In testimony whereof I aflix my signature in presence of two witnesses.

STEWART BRO'WN.

Witnesses:

N. C. STAFFORD, P. H. MOORE.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

